Abstract This application ?High throughput screen to identify small molecule analgesics targeting nNOS-NOS1AP protein-protein interactions? addresses the critical need for more effective medications to treat pain and, in particular chronic and neuropathic pain. Pain is the single-most common reason Americans access the health care system. Chronic pain affects ~116 million people in the USA. Current pain medications such as NSAIDS, steroids, opiates and gabapentin analogues have documented side effects, are ineffective in neuropathic pain or work only in subsets of patients. Chronic pain results in socioeconomic costs estimated at $560-635 billion annually. Activation of NMDA receptors (NMDAR) induces neuronal cell death and mediates central nervous system sensitization, which is implicated in the development and maintenance of pathological pain. NMDA induced excitotoxicity depends on formation of a multi-protein cascade complex at the receptor. Activation of the NMDAR leads to the recruitment of neuronal nitric oxide synthase (nNOS) by the post-synaptic density 95 protein (PSD95) to the signaling pathways which ultimately leads to neuronal cell death. Peptide disruptors of the NMDAR tripartite complex have been shown to be efficacious in stroke models and may also have fewer side effects than broad NMDAR antagonists. Small molecule inhibitors targeting the complex have potential as effective analgesics without the side effects associated with broad inhibition of NMDAR. A direct downstream effector of the NMDAR complex is nNOS-NOS1AP. A compound inhibiting this complex will likely be efficacious against stroke, neuropathic pain and other chronic neurological diseases precipitated by excitotoxicity. Anagin and its research partners at Indiana University have established a robust, high quality high-throughput assay to identify small molecule disruptors of nNOS-NOS1AP interaction, validated the assay and our approach in a pilot 10,000 compound small molecule library screen. In addition, Anagin has secondary in vitro selectivity and cell-based efficacy assays to perform hit-to-lead compound characterization as well as established collaborations to perform preclinical validation. In this Phase I SBIR program, the team will run an extensive small molecule screen to identify new druggable inhibitors with novel scaffolds that target nNOS-NOS1AP. Anagin will complete a small chemistry effort and initial administration- distribution-metabolism-excretion/toxicity studies to determine which compound series to advance as a lead molecule in a Phase II SBIR program for the treatment of chronic and neuropathic pain.